$ really gvinum list
1 drive:
D a                     State: up       /dev/ad0s2e     A: 100428/121908 MB (82%)

2 volumes:
V local1                State: up       Plexes:       1 Size:       1000 MB
V volatile              State: up       Plexes:       1 Size:         20 GB

2 plexes:
P local1.p0           C State: up       Subdisks:     2 Size:       1000 MB
P volatile.p0         C State: up       Subdisks:     1 Size:         20 GB

3 subdisks:
S local1.p0.s1          State: up       D: a            Size:        500 MB
S local1.p0.s0          State: up       D: a            Size:        500 MB
S volatile.p0.s0        State: up       D: a            Size:         20 GB

$ really gvinum printconfig
# Vinum configuration of nora.earthsim.tv, saved at Thu Mar  8 10:39:17 2007
drive a device /dev/ad0s2e
volume local1
volume volatile
plex name local1.p0 org concat vol local1
plex name volatile.p0 org concat vol volatile
sd name local1.p0.s1 drive a len 1024000s driveoffset 42967305s plex local1.p0 plexoffset 1024000s
sd name local1.p0.s0 drive a len 1024000s driveoffset 41943305s plex local1.p0 plexoffset 0s
sd name volatile.p0.s0 drive a len 41943040s driveoffset 265s plex volatile.p0 plexoffset 0s

$ cat add-subdisk
# How I added the second subdisk to the "local1.p0" plex...
sd name local1.p0.s1 length 500m plex local1.p0 drive a

$ really growfs /dev/vinum/local1
growfs: we are not growing (256000->256000)
>> 1!

$ really mount /dev/vinum/local1 /mnt

$ df -h /mnt
Filesystem           Size    Used   Avail Capacity  Mounted on
/dev/vinum/local1    484M    4.0K    445M     0%    /mnt